CN IX, X, XI, XII

Question 1

What are some of the functions of CN IX afferent fibers?

Answer 1

sensory for skin of ear and middle ear (superior ganglion of IX)
posterior 1/3 of tongue (taste, sensation, and motor) - inferior ganglion of IX
carotid body: Blood O2, CO2 & pH (inferior ganglion of CN IX & solitary nucleus)

Question 2

What are some of the funcitons of CN IX efferent fibers?

Answer 2

nucleus ambiguus: stylopharyngeus muscle

inferior salivatory nucleus: otic ganglion - parotid salivary gland

Question 3

T/F: nucleus ambiguus is a motor nucleus for parts of IX, X, and XI.

Answer 3

False. nucleus ambiguus is a motor nucleus for CN IX & X; not XI

Question 4

T/F: CN IX serves pain and temperature for skin of outer ear and uses spinal trigeminal nucleus.

Answer 4

True

Question 5

What are some of the functions of afferent fibers of CN X?

Answer 5

skin of ear (superior ganglion of X via trigeminal spinal nucleus)
epiglottis - taste & visceral sensation
thoracic and abdominal viscera
aortic arch baroreceptors (inferior ganglion of X via solitary nucleus)

Question 6

What are some of the functions of the efferent fibers of CN X?

Answer 6

nucleus ambiguus: lateral - muscles of speech and swallowing; medial - heart and lungs
dorsal motor nucleus of the vagus - all viscera up to transverse colon (parasympathetic)

Question 7

What fibers are involved in the gag reflex?

Answer 7

afferent: CN IX
efferent: CN X

Question 8

What fibers are involved in the tongue thrust reflex?

Answer 8

afferent: CN V or IX
efferent: CN XII